Windows in the walls give a view to colorful finches, a shiny scorpion, even a python named Cuddles.

This lush, gardenlike room is part of the Museum of Creation and Earth History, a beige, two-story structure that brings to life a version of history that isn't taught in public schools. Here, God created Earth as described in the Bible.

Each year, about 15,000 visitors come to Santee's only museum, deemed the world's largest creationist museum by the Northwest Creation Network. (A much larger, $27 million creationist museum under construction in Kentucky will soon snatch the title.) Folks may say they believe in evolution, but they don't really buy that humans came from other creatures, said John D. Morris, president of the Institute for Creation Research,...